Generally, a door has a hinge apparatus that provides restoration and absorbs shock. But in the conventional hinge apparatus, an elastic member providing restoring force and a damping device absorbing shock are all installed in one casing, thereby increasing the length of the hinge apparatus. And thus a buried type hinge apparatus is required to be buried more deeply, making it difficult to manufacture burying holes depending on door materials.
Further, a certain period of repeated opening and closing of a door lowers a restoring force of an elastic member, thus it needs to be replaced with a new one, or used in a bad state. And when coupling a connection frame of a door with a shaft, inaccurate coupling of an end portion of a shaft with a connection frame of a door makes an initial coupling difficult, thereby worsening the adhesion of a hinge axis and doorframe. And the metal to metal scratching noise is made due to a galled metal.
Korea Patent Publication No. 2001-0027832 discloses a hinge apparatus having an automatic return function. The hinge apparatus has such a complex structure that assembly productivity deteriorates. A compression spring is used as an elastic member for an automatic return, thereby leading to a weakening of the restoring force, and it is difficult to be buried in a door. Further, the conventional hinge apparatus with an automatic return function is not height-controllable when used in a buried type. Thus in the case of a two-door type that opens and closes from both sides, if the doors have different heights, it is difficult to adjust the height of doors at user's discretion.
There is disclosed a hinge apparatus with an automatic return function to solve the problems of the conventional arts.